The present invention relates to a light-polarizing film.
In conventional liquid crystal projectors incorporating liquid crystal panels, such as so-called video projectors, data projectors and the like, beams of the three primary colors of red (R), green (G) and blue (B) are respectively applied to liquid crystal panels for red, green and blue to obtain respective images of the three primary colors. The resultant images are synthesized and projected by means of dichroic mirrors or the like. The beam of each primary color is obtained through spectral-separation of white light from a metal halide lamp, high-pressure mercury lamp or the like, by means of the dichroic mirror or the like. Such a liquid crystal panel normally employs a light-polarizing plate wherein protective sheet(s) are bonded to one or both sides of a so-called neutral-gray light-polarizing film. As the light-polarizing film, a light-polarizing film with an absorbedly oriented dichroic dye is frequently employed in view of its resistance to heat and light from the light source.
Unfortunately, a conventional liquid crystal projector with the neutral-gray light-polarizing film has a problem in that a displayed image often appears yellowish to the eye. The problem of the yellowish image display may be solved by reducing the amount of light for red and green relative to that for blue. However, the reduced amount of light results in a lowered image lightness.
After an intensive study to develop a light-polarizing film for a liquid crystal projector featuring a bright and natural color display, the present inventors have found that a bright and natural color display is attained by applying a light-polarizing plate comprising a light-polarizing film with specific light transmitting characteristics to the liquid crystal panel for blue of the liquid crystal projector, thus achieving the present invention.
A first object of the present invention is to provide a light-polarizing film which possesses a light transmittance of not more than 0.3% at wavelengths of from 430 nm to 500 nm inclusive when irradiated with a linearly polarized light with a vibration plane parallel to an absorption axis and a light transmittance of not less than 77% at wavelengths of from 430 nm to 500 nm inclusive when irradiated with a linearly polarized light with a vibration plane perpendicular to the absorption axis.
A second object of the present invention is to provide a light-polarizing plate which comprises the above-described light-polarizing film and possesses a surface reflectance of not more than 1% at wavelengths of from 430 nm to 500 nm inclusive.
A third object of the present invention is to provide a light-polarizing plate which possesses a light transmittance of not more than 0.3% at wavelengths of from 430 nm to 500 nm inclusive when irradiated with the linearly polarized light with the vibration plane parallel to the absorption axis, a light transmittance of not less than 77% at wavelengths of from 430 nm to 500 nm inclusive when irradiated with the linearly polarized light with the vibration plane perpendicular to the absorption axis, and a surface reflectance of not more than 1% at wavelengths of from 430 nm to 500 nm inclusive.